#include <iostream>
#include <stack>
#include <queue>
using namespace std;

int main()
{
    string s;
    cin>>s;
    stack<char>l1;
    queue<char>l2;
    for (int i=0;i<s.size();i++)
    {
        l1.push(s[i]);
        l2.push(s[i]);
    }
    while (!l1.empty())
    {
        if (l1.top()!=l2.front())
        {
            cout<<"no";
            return 0;
        }
        l1.pop();
        l2.pop();
    }
    cout<<"yes";
    return 0;
}